Cutterhead construction for dry shavers



Oct. 14, 1941. KNAPP 2,259,002

CUTTERHEAP CONSTRUCTION FOR DRY SHAVERS Filed Aug. 1, 1938 2 Sheets-Sheet l ATTORNEYS.

Oct. 14, 1941. R KNAPP CUTTERHEAD CONSTRUCTION FOR DRY SHAVERS 2 Sheets-Sheet 2 Filed Aug. 1, 1958 1N VENT OR. 220$ m0 flrz 3%? w ATTORNEYS.

Patented Oct. 14, 1941 r.

ATE-NT; soreness 1 An object of my invention is to provide a cutter head construction for dry shavers which is simple and inexpensive to manufacture and whichincludes novel features of construction whereby to improve-the hair-cutting action of the shaver.

Another object is to provide a cutter head construction including an outer cutter plate formed of sheet metal and having openings'therein to receive the hair, the sheet metal being depressed adjacent the edges of the openings to form grooves which-guide the hair into the openings, the general direction of the grooves being substantially parallel to the'line of advance ofthe outer cutter plate across the skin'of the user.

Still another object is to provide an inner cutter which so coa'cts with the teeth of the outer cutter and with the sheet metal at the ends of the grooves that any hair projecting through the openings of the outer cutter plate adjacent the groove ends is efiectivelysheared off'between the inner cutter teeth and the metal of the-outer cutter plate at the ends of the grooves.

A further object is to provide means to urge theinner cutter into shearing coaction with the outer cutter, which means includes rollers,'pins and spring means to urge the pins andthereby th rollers toward the inner cutter.

Still a further object is'to provide the hairguiding grooves in connection with various types of cutters, the grooves being'arrangedibetween spaced series of openings in the outer cutter plate or at the ends of transverse slots wherethe grooves serve to guide the hair into the slots during' the return stroke'of the cutter across the skin of the user.

With these and other objects in View, the invention: resides in certain improvements; and in acombination'of parts of the device, all'as will hereinafter more fully be described and-the novel features will be'pointedout in the claims appended to the application. 1 I

In the accompanying drawings:

Figure l is a-sectional view through a cutter head construction for dry shavers embodying my invention, a portion of the shaver head receptionend of the dry shaver motor being illustrated and aportion of the actuating arm for the inner cutter being shown-in this figure;

Figure 2 is a similar sectional view showing only the skin-engaging end of the cutter, with the parts enlarged so as more clearly to illustrate the invention;

- Figure 3 is a fragmentary perspective view of the outer and inner cutters,the twobeing shown in coaction'with each other head construction including the inner and outer cutters, portions thereof being broken away'a'nd other portions shown insection to illustrate'the co'a'ction' of different parts of the"'device' -'with each other;

- Figure 6 is'an elevational view, "as on the; line 66 of Figure 5, showing a modified construction;

Figure 7 is a fragmentary s'ide elevation of the modification shown in Figure 6; Figure 8 is a sectional view on theline 8 8 of Figure 6;

' Figure '9 is a sectional View as "on the. line 9-'-9 of Figure 5; showing another. modification;

Figure 10 is a fragmentaryside elevation thereof, and

Figure 11' is a sectional View on the'line H--"! l of Figure 9.

On the accompanying drawings, I'have' used the reference character A toiindicate an outer cutter plate and B an inner'cutt'er member; The plate A has a semi-cylindrical skin-engaging'portion It and side plateportions l2. Between the side plate portions Itfilteiwblocks l3 are-provided'and reinforcing blocksz'l' arelocated outside the'side plates I2; The outer cutter plate A, the blocks l3 and-the-bloclz's 2| areassembled "by riveting them together. The rivets are-indicated at M.

The cutterplate A is provided -withop'enings such as slots l5 whereby the-metal between the slots serves as outer cutterteeth; "The inner cutter B has cutter teeth IGfor-shearing coaction with the teeth of the'outer cutter upon'reciprocation" of i the inner cutter relative to the outer cutter. Such reciprocation isefiected -by an oscillating 'arm' I! pivoted at-IB'a-nd operated'by an electric motor (not shown -in a casing-19in 25 of one-of the plates 21 tofirmly retainthe outer cutter withinthe head member 23.

In connection with the operation of dry'shavers, I find that-theshaver has-to-bepassed across the skin several times in order to cut all the beard. I have also found that the number of -such--pas sages can be materially reduced by providing guide grooves 26 having their ends terminating at the openings l for guiding the hairs into the openings so that they can be sheared 01f.

Where the outer cutter plate is of sufficient thickness, I can cut the grooves therein. Ordinarily, however, it is desirable to have the plate quite thin or formed of thin sheet metal in which case I form the grooves 26 by depressing them into the sheet metal so that the depressed portion of the sheet metal forms an internal bead 21. This bead, in addition to serving the purpose of permitting the groove 26 to be formed in the sheet metal without materially reducing its thickness, serves to reinforce the sheet metal against bending and distortion.

The grooves 26 are arranged in the general direction of advance of the outer cutter plate across the skin of the user, or in otherwords transversely of the longitudinal axis of the cutter head. The grooves 26 appear as in Fig. 4, when viewed on the line 44 of Fig. 3, and it will be noted that this produces an offset in the sheet metal adjacent the upper ends of the slots I5. The ends of these offsets are indicated at 28. The upper ends of the cutter teeth l6 as indicated at 29 engage the shoulders formed at 28 and thereby shearingly coact with them so that any hair getting into the slots l5 and being positioned at the upper ends thereof at the time a tooth l6 passes the slot will be effectively sheared off between the portions 28 and 29.

To retain the portions 28 and 29 in shearing contact with each other and also to retain the sides of the teeth H5 in shearing contact with the sheet metal of the outer cutter plate A between the openings I5 therein I provide an improved biasing means comprising springs 30, pins 3] and rollers 32. The springs 30 are located in bores 33 formed in the filler blocks l3. They are retained therein by plugs 34 and the upper or outer ends of the springs engage the pins 3|. The rollers 32 are located in the outer ends of the springs and journaled on the pins 3|. The ends of the pins are located in notches 35 of the filler blocks l3 and are retained therein against being expelled therefrom by the springs 30 in any suit able manner when the inner cutter is removed from the outer cutter. By way of illustration, I show deformations at 36 in the edges of the notches 35 to accomplish this result.

There are certain types of cutter heads as shown in Figs. 6 and 9 which have transverse slots a extending across the outer cutter plate A or A and terminating in the side plates [2a thereof. Hair guiding grooves 26a may be provided for this type of cutter arranged at the opposite ends or bases of the slots [5a. The grooves are preferably in alignment with the direction of advance of the cutter head on the return stroke thereof so that they guide the hair into the slots. Various parts in these two figures, other than those just enumerated, correspond to the preceding figures and are therefore given the same reference numeral with the addition of the letter a.

In Figure 6 the inner cutter is illustrated at B and in Figure 9 at B". The inner cutter B is formed of sheet metal so shaped as to accommodate the beads 21a and is formed with an offset to provide the shoulders 28a. The inner cutter B", in Figure 9, may be machined from a solid piece of metal and notched to form its shoulders at 28a. In Figures 8 and 11, the relationship of the inner cutter teeth Ilia to the sheet metal between the openings I5a for shearing coaction therewith is illustrated.

The grooves 26 and 26a I find very effective for the purpose of guiding the hairs into the slots l5 and [5a and for aiding in the process of causing the hairs to stand erect before they enter the slots. Obviously the shearing of the hairs is thereby facilitated. The pressure of the edges of the grooves against the skin results in the portion of the skin in the grooves bulging toward the cutter head and thereby aiding in the erection of the hairs.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention. I therefore intend to cover any modified forms of structure or use of mechanical equivalents which may be reasonably included within the scope of my appended claims.

What I claim as my invention and desire to protect by Letters Patent of the United States Patent Ofiice is:

1. In a cutter head construction for dry shavers, an outer cutter plate formed of sheet metal, said plate having therein a plurality of spaced openings whereby the portions of the sheet metal between said openings form outer cutter'teeth, an inner reciprocable cutter having teeth for shearing coaction with said outer teeth, a groove depressed in said outer cutter plate for each opening therein and terminating at an end of the opening, said inner cutter terminating at said ends of said openings and the metal of said outer cutter in which said grooves are formed, engaging the terminal end of said inner cutter, said grooves being arranged in a direction substantially lateral to the direction of reciprocation of said inner cutter plate relative to the skin of the user.

2. In a cutter head construction for dry shavers, an outer cutter having therein a plurality of spaced elongated openings whereby the portions of the outer cutter between said openings form cutter teeth, an inner cutter having teeth for shearing coaction with the cutter teeth of said outer cutter, a depressed groove in said outer cutter for each opening therein and terminating at an end of the opening and said inner cutter having tooth ends engaging the material of said outer cutter that was displaced in forming the grooves, said grooves being arranged substantially parallel to said elongated openings of the outer cutter plate.

3. In a cutter head construction for dry shavers, an outer cutter member having a series of openings therein arranged in a plurality of spaced groups, an inner cutter having teeth to shearingly coact with the portions of said outer cutter member between said openings and grooves in said outer cutter member between said groups of openings and aligned with the openings, the opposite ends of said grooves terminating at the ends of said openings.

4. In a cutter head construction for dry shavers, an outer cutter plate formed of sheet metal and having a series of openings therein arranged in a pair of spaced rows, an inner cutter having teeth to shearingly coact with the portions of said outer cutter member between the openings therein and grooves depressed in the metal of said outer cutter plate and arranged to extend transversely across said outer cutter plate from one row of openings therein to the other with the opposite ends of said grooves terminating at the endsoi said openings.

5. In a cutter head construction for dry shavers, an outer cutter plate formed of sheet metal, said outer cutter plate having a series of openings therein arranged in a plurality of spaced groups, the portion of the sheet metal between said openings forming outer cutter teeth, a reciprocable inner cutter having teeth to shearingly coact therewith and grooves depressed in the metal of said outer cutter plate and arranged to extend between said groups of openings, the opposite ends of said grooves terminating at the ends of said openings and being arranged in a direction substantially normal to the line of reciprocation of the inner cutter relative to the outer cutter plate.

6. In a structure of the character disclosed, an outer cutter plate formed of sheet metal, said cutter plate being bent to form an arcuate outer surface and a pair of sides, elongated openings extending transversely of said cutter and terminating in said sides, an inner cutter having teeth to shearingly coact with the edges of said openings and grooves depressed in said sheet metal outer cutter plate, there being one groove for each of said openings and said grooves terminating at the ends of the openings and being of a depth substantially equal to the thickness of said outer cutter plate.

7. In a cutter head construction for dry shavers, an outer cutter plate formed of sheet metal and having a plurality of spaced openings therein whereby the portions of the sheet metal between the openings constitute outer cutter teeth, an inner cutter having teeth to shearingly coact with said outer teeth and grooves depressed in said outer cutter plate for the openings therein, said grooves terminating at the ends of said openings and being arranged in a direction substantially parallel to the line of advance of the outer cutter plate relative to the skin of the user, said inner cutter having notched portions of its teeth adjacent said edges of said openings arranged in contact with the ends of the depressed portions of the sheet metal at the ends of said openings to shearingly coact with said ends of the depressed portions.

8. In a cutter head construction for dry shavers, an outer cutter member having a plurality of hair-reception openings therein, an inner cutter having teeth to shearingly coact with the edges of said openings and a depressed groove in said outer cutter member for each opening therein, said grooves terminating at the ends of said openings, said inner cutter having portions of its teeth adjacent said ends of said openings arranged in longitudinal alignment with said grooves and in contact with those portions of said outer cutter member that constitute the ends of said grooves to shearingly coact therewith.

RAYMOND KNAPP. 

